Assignment Class-IX Mathematics Topic – Surface area and volume
1.The diameter of garden cylindrical roller is 2.8m long . How much area will it cover in 100 revolutions.
2. A rectangular piece of paper 16 cm by 3.5cm is rotated about the longer side. Find the total surface area of the solid so generated.
3. In a hot water heating system, there is a cylindrical pipe of length 35m and radius 4cm find the total radiating surface in the system
4. Find the curved surface area of the right circular cone whose slant height is 10cm and base radius is 7cm.
5. The lateral surface area of the right circular cone of radius 12cm is 489.84 cm2 . Find the height of the cone .
6. Find the surface area of the sphere of radius 7cm.
7. A solid cube of side 14cm is cut into 64 cubes of equal volume. What will be the side
of the new cube . Also find the ratio between their surface area.
8. The capacity of a cuboidal water tank is 240000 liters . Find the depth of the water tank if its length and breadth are 5m and 3m respectively.
9.Find the capacity of a cold storage of breadth 4.5m, height 3m and length double its breadth
10. Slant height and depth of a conical pit are 35cm and 28cm respectively . Find the volume of a conical pit.
11. The base radii of two right circular cones of same height are in the ratio 4:7. Find the ratio of their volumes.
12.The dimensions of a cuboid are in the ratio 2:3:4 and its total surface area is 8788cm2. Find the dimensions of the cuboid.
13. A closed cuboidal iron water tank is 12m long, 9m wide and 4m high is to be made from an iron sheet of breadth 2m . Find the cost of iron sheet at the rate of Rs 45 per metre.
14. The diameter of a cylindrical road roller is 98cm and its length is 150cm. It takes 750 revolutions to move once over a road to level it . Find the cost of leveling the road at the rate of Rs.2.50 per m2
15. The inner diameter of a cylindrical pit is 56cm and it is 240cm deep. Find : (i) its inner curved surface area (ii) its total inner surface area (iii) the cost of plastering the inner surface area at the rate of Rs. 43 per square metre.
17. How many metres of cloth, 5m wide will be required to make a conical tent of base radius 7m and height 24m ? Also find the cost of the cloth at the rate of Rs 45 per metre.
18. A joker’s cap is in the form of a right circular cone of base radius 5cm and height 12cm. Find the area of the sheet required to make 15 such caps.
19. A right triangle ABC with sides 5cm, 12cm and 13cm is revolved about the side 12cm and 5cm respectively . Find the ratio of the total surface area of the two cones so formed.
20. A cylinder , a cone and a sphere are of the same diameter and same height . Find the ratio of their curved surface .
21.The radius of the spherical balloon increases from 10.5cm to 14cm as air is being pumped into it. Find the ratio of surface area of the balloon in the two cases.
22. Water in a river , 3m wide and 1.2m deep, is flowing at the rate of 20km per hour . How much area will it irrigate in half an hour, if 10cm of standing water is desired.
22. Find the mass of metallic hollow cylindrical pipe 24cm long with internal diameter 10cm and made of 5mm thick metal, if 1cm3 of the metal weighs 7.5g.
23. A shot- put is a metal sphere of radius 4.9cm. If the density of the metal is 7.8g per cm3. Find the mass of the shot –put.
24. A brass bowl is in the form of a hemisphere . The cost of tin plating it on the inside at the rate of Rs 16 per 100 cm2 is Rs 27.72. Find the : (i) inside surface area of the bowl (ii) volume of the air inside the bowl
provide solution
ReplyDeleteplease